Motor fuel and method of preparing the same



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Patented Dec. 24, 1940 UNITED STATES 2,225,942 PATENT OFFICE MOTOR FUEL AND METHOD OF PREPARING THE SAME Helmuth G. Schneider, Roselle, and William H. Smyers, Westfleld, N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application November 20, 1936,

Serial No. 111,846 1 1 Claim.

' taining one or more branched aliphatic hydrocarbon groups without the use of a metallo-organic anti-knock agent.

Although certain types of ketones have already been used in motor fuels without any metalloorganic anti-knock agent, their use has generally been attended with either some difliculty from the point of view of manufacturing, storing, distributing or utilizing the blended fuel, or the particular ketone addition agents used did not impart to the gasoline base stock a suflicient improvement in octane number or other properties to warrant the extra cost'of the addition agent. For instance, although acetone is known to improve the anti-knock properties of gasoline, its preferential solubility in'water compared to the gasoline base stock is so great, that when the blend is stored over water, a large proportion of the acetone is removed. On the other hand, if one attempts to increase the stability of a blended fuel containing ketones during storage over water, by using ketones of a higher mol. wt. (compared to the acetone which is methyl methyl ketone) for example, methyl ethyl ketone, methyl propyl ketone or methyl butyl ketone, it is found that ketones having more than a total of about 5 carbon atoms hare proportionately lower anti-knock properties as the molecular weight increases as shown in the following table.

High-grade gasoline base stock.

It has now been found that if ketones are used containing one or more branched aliphatic hydrocarbon groups, it is not only possible to use ketones having a substantially greater number of carbon atoms and higher molecular weight, but these compounds have been found to have unexpectedly high anti-knock properties, in fact, substantially higher than those having the same number of ca:bon atoms but having only substantially straight chain aliphatic groups as is shown by the following table:

Table 2 Imprgve- A. s. T. M. Test 5;: Kctone added octane numoctage 0. her 212 F.

' due to ketones 6 None 75.0 7 25 Methyl n-butyl ketone 78.0 3. 0 8 25 Methyl iso-butyl ketona 81.1 6. 1

High grade gasoline base stock. I

The above table shows that the methyl butyl ketone containing the iso-butyl group obtained twice as great an octane number improvement as did the one having a normal-butyl group. On the other hand, the iso compound has substantially the same solubility in gasoline as the normal compound.

It should be mentioned that another advantage of the present invention is that due to the higher anti-knock properties of the highly branched ketones it is possible to use ketones having so much higher molecular weight that their oxygen content becomes relatively negligible as a factor in reducing the fuel value of the gasoline base stock with which it is blended.

Other examples of ketone containing branched aliphatic hydrocarbon groups, in addition to the methyl isobutyl ketone (B. Pt. 116 C.) mentioned above, include methyl isopropyl ketone, ethyl isopropyl ketone, propyl isopropyl ketone, methyl tertiary butyl ketone, methyl iso-amyl ketone, methyl tertiary amyl ketone, tertiary butyl acetone (C4H9 CHzCOCHa), (ii-isopropyl ketone, isopropyl tertiary butyl ketone, (ii-isobutyl ketone (B. Pt. 181 0.), di-tertiary butyl ketone and ditertiary amyl ketone.

Ketones having quaternary carbon atoms are most desirable. Of those containing tertiary carbon atoms the ones containing the shorter side chains attached to the tertiary carbon atom are most preferable, namely, those containing isopropyl groups.

Best results are obtained by employing ketones having branched chains on each side of the carbonyl radical although their expense'may not always justify their use. Of the ketones having a branched chain on but one side of the carbonyl radical, those having a methyl group rather than longer straight chain radicals on the- OPP Si e Side are most desirable.

Particularly preferred ketones having branched chains on both sides of the carbonyl radical are di-isopropyl, di-tertiary butyl and lsopropyl tertiary butyl ketones; of those having a branched chain only on one side of the carbonyl radical, methyl-isopropyl and methyl tertiary butyl are particularly preferred.

Other types of ketones which may be used include those having the general formula R.CO.R' in which R represents an aryl group, e. g. phenyl, benzyl, toluyl, etc., or a more saturated cyclic group, and R is a branched aliphatic hydrocarbon group such as isopropyl secondary butyl, tertiary butyl and the like.

Instead of using single ketone compounds, a preferred branched ketone may be used in conjunction with other branched ketones or with other preferably low molecular weight, ketones not having a branched structure, (e. g. not having more than 5 carbon atoms), also ketones containing two or more carbonyl groups may be used.

It is preferred to use ketones which are liquid at normal atmospheric temperatures and fairly easily volatilized with the gasoline hydrocarbons.

Also, unsaturated ketones containing one or more branched aliphatic hydrocarbon groups may be used, for instance, mesityl oxide, which is methyl isobutyl ketone containing a double bond and having the formula (CH3)2C:CH CO CH: and phorone having the formula (CH3)2 CICH CO CH: C (CH3)2 and substituted branched ketones such as those containing hydroxyl groups, e. g. di-acetone alcohol, COH

(CH3)2 CH2 CO CH3.

As illustrative of several of the latter types of compounds, the following tests are given:

It is noticed in Table 3 that the anti-knock properties of the mesityl oxide (which may be considered as unsaturated methyl isobutyl ketone) and of the di-acetone alcohol (which may be considered as a hydroxy derivative of methyl isobutyl ketone) compare favorably with the anti-knock properties of methyl isobutyl ketone itself, as shown in Table 2, although the latter, the unsaturated unsubstituted compound, is slightly superior.

It is thus seen from the above data that motor f s of high octane number can be obtained by in carrying out the invention may be a petroleum naphtha derived from either a single or a mixed crude and may be a straight run naphtha or a cracked naphtha or a blend. This base stock should, of course, meet whatever specifications for stability, gum, corrosion, etc., required for finished blended motor fuel. Other types of hydrocarbon liquids may also be used, such as hydrogenated naphtha prepared by destructive hydrogenation of hydrocarbon liquidsboiling in the range of gasoline, kerosene and lubricating oil, or a reformed naphtha, or a light liquid fraction prepared by polymerization of lower boiling or gaseous olefines.

Generally the boiling point of the ketone to be used should be within the boiling range of the gasoline, or in other words, between the approximate limits of 100 F. to 400 F., or roughly, between C. and about 210 C. Generally, ketones of the type described and having a total of about 5 to 10 or 11 carbon atoms fulfill this requirement most effectively.

The amount of ketone to be blended with the gasoline base stock will depend primarily upon the octane number of the base stock itself and the octane number desired in the finished blend. In a general way, the improvement in octane number due to the ketone is directly proportional to the amount of ketone used, and for ordinary purposes the amount of ketone added should be between the approximate limits of 5 and or more, usually 10 to 30% being sufficient.

If desired other known motor fuel addition agents may be used such as antioxidants, gum inhibitors, dyes, upper cylinder lubricants, gum fluxes, metallo-organic anti-knock agents of the lead tetraethyl type as claimed in the original application referred to above, and other organic liquids having high anti-knock blending value.

In the appended claim the expression a ketone is intended to mean either a single compound or a mixture of several ketones.

It is not intended that this invention be limited to any of the specific examples which are given herein only for the sake of illustration, nor to any theories as to the operation of the invention, but it is to be limited only by the appended claim in which it is intended to claim all novelty inherent in the invention as broadly as the prior art permits.

We claim:

A motor fuel comprising gasoline and diisopropyl ketone in which the di-isopropyl ketone forms from 5 to 50% of the fuel.

HELMUTH G. SCHNEIDER. WILLIAM H. SMYERS. 

